@article{MAN_1988__281_4_164424,
     author = {Pawel Szeptycki and Iwo Labuda},
     title = {Extensions of {Integral} {Operators.}},
     journal = {Mathematische Annalen},
     pages = {341--354},
     publisher = {mathdoc},
     volume = {281},
     number = {4},
     year = {1988},
     zbl = {0617.45013},
     url = {http://geodesic.mathdoc.fr/item/MAN_1988__281_4_164424/}
}